Sexual Satisfaction among Lesbian and Heterosexual Cisgender Women: A Systematic Review and Meta-Analysis

Background: Sexual satisfaction is a complex, multifaceted, and broad concept that is influenced by several factors. The minority stress theory posits that sexual and gender minorities are at a particular risk for stress due to stigma and discrimination at the structural, interpersonal, and individual levels. The aim of this systematic review and meta-analysis was to evaluate and compare the sexual satisfaction between lesbian (LW) and heterosexual (HSW) cisgender women. Methods: A systematic review and meta-analysis were conducted. We searched the PubMed, Scopus, Science Direct, Websci, Proquest, and Wiley online databases from 1 January 2013 to 10 March 2023 to identify the published observational studies on sexual satisfaction in women according to their sexual orientation. The risk of bias in the selected studies was assessed using the JBI critical appraisal checklist for the analytical cross-sectional studies. Results: A total of 11 studies and 44,939 women were included. LW reported having orgasms during a sexual relationship more frequently than HSW, OR = 1.98 (95% CI 1.73, 2.27). In the same direction, the frequency of women reporting “no or rarely” for having orgasms during their sexual relationships was significantly lower in the LW than the HSW, OR = 0.55 (95% CI 0.45, 0.66). The percentage of the LW who reported having sexual intercourse at least once a week was significantly lower than that of the HSW, OR = 0.57 for LW (95% CI 0.49, 0.67). Conclusions: Our review showed that cisgender lesbian women reached orgasm during sexual relations more often than cisgender heterosexual women. These findings have implications for gender and sexual minority health and healthcare optimization.


Background and Rational
The minority stress theory posits that sexual and gender minorities are at a particular risk for stress due to stigma and discrimination at the structural, interpersonal, and individual levels [1]. This stress, in turn, elevates the risk of adverse health outcomes across several domains, including sexual satisfaction.
Many studies have pointed out that sexual minorities experience significant health disparities [2][3][4]. These differences are associated with a model of intersectionality that includes social, biological, and economic components [5]. Despite this multidimensionality, the differences described focus primarily on mental health [6,7], sexually transmitted infections and diseases, body image changes, and eating disorders [8,9]; however, sexual well-being, despite its importance, is not usually taken into account in these analyses.
Sexual satisfaction is a complex, multidimensional, and broad concept that includes individual, relational, and contextual dimensions [10] and is conceptualized as a sexual right by the World Health Organization [11] and the World Association for Sexual Health [12][13][14]. According to Meston and Trapnell, 2005 [15], sexual satisfaction in women is described as a multifaceted construct that includes relational dimensions such as compatibility between

Study Design
The PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) [19] and recommendations of the Cochrane Handbook were followed [20]. There were no requirements for an ethical review of this work, because no human participants were involved.

Search Strategy
We searched the PubMed, Scopus, Science Direct, Websci, Proquest, and Wiley online databases from 1 January 2013 to 10 March 2023 to identify the published observational studies on sexual satisfaction in women according to their sexual orientation.
The search strategy used in PubMed is described below. The strategy was modified accordingly for its use in the other databases.

Inclusion and Exclusion Criteria
The inclusion criteria were: 1. studies of a cross-sectional, observational type (including cross-sectional analyses of longitudinal studies); 2. participants: >18 years old; heterosexual and lesbian cisgender women; 3. comparison group/condition of interest: Healthcare 2023, 11, 1680 3 of 13 sexual orientation (heterosexual versus lesbian); 4. primary outcome: sexual satisfactionorgasm frequency; 5. secondary outcomes: the frequency of sexual intercourse and arousal difficulties; and 6. settings: community. The exclusion criteria were: 1. studies exclusively focused on transgender or nonbinary subjects; 2. global outcomes for lesbian and bisexual subjects; and 3. experimental studies.

Screening and Data Extraction
An initial screening of the titles was conducted by (AM) based on the inclusion criteria. Duplicates and studies clearly not associated with the review objectives were excluded. Then, the abstracts were independently screed by two reviewers (AM and EC) based on the above-established criteria. The relevant studies and those in which the abstract raised doubts had their full texts independently evaluated by the two reviewers.
All disagreements were solved by consensus.
The following data were then extracted from the included studies: the first author, publication year, country, study design, sample size, study population details, outcomes, results, and authors' main conclusions.
Sexual satisfaction was evaluated through various parameters, which included the frequency with which the women reached orgasm in a sexual relationship, the degree of difficulty in becoming aroused, pain during or after sex, a lack of interest in sex, the frequency of sexual activity, and global sexual satisfaction.

Risk of Bias Assessment
Two reviewers independently assessed the risk of bias in the selected studies using the JBI critical appraisal checklist for analytical cross-sectional studies [21]. This tool used eight criteria to evaluate the overall methodological quality of a study. The criteria included: the sample inclusion criteria; a description of the subjects and settings; a valid and reliable measure of exposure; an objective and standard measure of condition; identifying confounding factors; strategies for dealing with confounding factors; a valid and reliable measure of outcome; and an appropriate statistical analysis. Disagreements were resolved through discussion.

Meta-Analysis
The RevMan 5.4.1 (The Cochrane Collaboration) online software was used. Comparable data from studies with similar populations and outcomes were pooled using forest plots. The odds ratio (OR) with 95% confidence intervals (CIs) for dichotomous data was used as the effect measure. The statistical heterogeneity among the selected studies was measured by using I 2 in each analysis and a 5% significance level. The random effect model was selected for the analysis carried out, because the true effect sizes underlying all the studies were stochastic.
A sensitivity analysis was conducted to evaluate the robustness of the results by excluding individual studies for each forest plot.

Search Results and Study Characteristics
The details of the literature search and screening process can be found in Figure 1. A total of eleven studies were selected for this review. The included studies were published between 2014 and 2022. A total of 44,939 women were included, from Australia, Germany, Portugal, Spain, Sweden, the United Kingdom, and the United States. The mean age was 31 years, most participants were white, and more than two thirds had a college degree or had attended a university. The studies' risk of bias assessment is presented in Table 1. Characteristics of the studies' populations and studies' main results are described in Tables 2 and 3. degree or had attended a university. The studies risk of bias assessment is presen Table 1. Characteristics of the studies populations and studies main results are des in Table 2 and Table 3. In general, the studies recruited their samples online, using several methodo that included posting ads on social networks and websites specifically targeting p belonging to sexual and gender minorities, and through direct contact with respon in a snowball approach.    Participants included men and women who self-identified as heterosexual, gay, lesbian, or bisexual who lived in Australia, North America, or the UK. Were recruited online via posts to various sub-categories of a social news and entertainment-sharing website, where registered users can submit content to share with others. The posts asked for volunteers between 18 and 65 years old to participate in a survey on sexiness and provided a link to an online questionnaire. Participation was voluntary and no incentive was provided.
Australia, North America, UK Batz, 2022 [23] Anonymous nationwide online survey. To spread the questionnaire online, invitations with a link to access the survey were shared via e-mail distribution lists and on social communication networks such as Facebook, Instagram, Twitter, and WhatsApp. Participants were invited to forward the link of the survey (snowball sampling). Cross-sectional study design was carried out during the first confinement in Germany from 20 April to 20 July 2020. Inclusion criteria were a minimum age of 18 years and German language skills. Data collection in 2020.
Björkenstam, 2020 [18] Data from sexual and reproductive health and rights (SRHR) 2017, based on a Swedish national sample of women and men aged between 16 and 84 years. The paper questionnaires were mailed and the respondents also received an information letter on the survey and its purpose. The respondents were also informed that the questionnaire would be supplemented with register data and that participation was voluntary and anonymous. Data collection in 2017. Cross-sectional surveys were administered by KnowledgePanel ® (GfK), an online panel that uses address-based probability sampling and is representative of the civilian, noninstitutionalized US population. Eligibility criteria for both samples included age of 18 years or older and ability to read English. Data collection in 2013-2014.      Among women, we did not find differences in satisfaction by sexual orientation. COVID-19 pandemic and resulting social constraints had a particular impact on the sexual health of LW.
Garcia, 2014 [27] Percentage of sex that includes orgasm Percentage of sex that includes orgasm-HSW 75%, L 90 %, B 72%; frequency of orgasm-"never": HSW 7.5%; LW 2.2%; and frequency of orgasm-"usually always": 51.2%, 71.5% In their rates of orgasm occurrence, LW had higher average mean occurrence rates than HSW did. LW reported higher mean orgasm occurrence rates and higher intraindividual variation than HSW did; that is, LW responses were more widely distributed than those among HSW.
Holt, 2020 [28] Frequency of sexual activity (past 12 months); orgasm frequency; arousal difficulties; and sexual problems Frequency of sexual activity-more that once a week: HSW 55.6% LW 46.6%; orgasm with partner-"most of the time": HSW 68.4% LW 79.4%; orgasms-"never": HSW 5.2% LW 2.9%; arousal difficulties-HSW 15.8% LW 8.3%; sexual problems-"not at all": HSW 47.7% L 57.4% HSW may be more likely to use the role of sexual activity in the relationship as a key barometer for the sexual health of the relationship; LS thought the use of sex materials and experiences with additional partners were more important than HSW did.
Minority sexual identities may reflect an associated comfort with sex positivity and disregard of more traditional, sex-negative values.
Joyner, 2020 [29] Satisfaction sexual relation (0 to 1) Satisfaction sexual relation-mean (sd): HSW 0.82 (0.01) LW 0.80 (0.03) Before and after controlling for a rich set of variables, male and female respondents in same-sex relationships failed to differ from their counterparts in different-sex relationships in their levels of commitment, satisfaction, and emotional intimacy.
Moreno-Domínguez, 2019 [30] Frequency of sexual activity Frequency of sexual activity-more that once a week: HSW 65.9% LW 68.3% No sexual-orientation-based differences were found for frequency of sexual activity, relationship status, or sexual dissatisfaction. However, body dissatisfaction did exert a lesser influence on sexual dissatisfaction in LW compared to HSW.
Peixoto, 2015 [31] Orgasmic difficulties, lack of sexual desire, arousal difficulties, and sexual pain Experienced difficulties in reaching orgasm-HSW 11.5% LW 6.7%; lack of sexual desire-HSW 9.8% LW 6.7%; arousal difficulties-HSW 8.9% LW 5.6%; and experienced sexual pain-HSW 13.3% L 9.8% Findings suggested specificities in frequency of self-perceived sexual problems, according to sexual orientation. Overall, findings indicated that HSW reported more sexual problems than LW did. Current data suggest that LW reported fewer difficulties in reaching orgasm.
In general, the studies recruited their samples online, using several methodologies that included posting ads on social networks and websites specifically targeting people belonging to sexual and gender minorities, and through direct contact with respondents in a snowball approach.

Risk of Bias
The risk of bias in the included studies was low. The major weakness of the studies was in the control of the confounding variables, which was not performed in six of the eleven studies.

Sexual Satisfaction Results
Sexual satisfaction was evaluated in five studies. Although the evaluation methodologies were different, and were therefore not directly comparable, the studies showed no significant differences between LW and HSW in this global assessment.

Frequency of Sexual Intercourse
The frequency of sexual intercourse was presented in four studies involving 5339 women, showing a lower frequency for LW when compared to HSW.
A fixed-effects Mantel-Haenszel (M-H) model meta-analysis showed that the percentage of LW who reported having sexual intercourse at least once a week was significantly lower than that of HSW, OR = 0.57 for LW (95% CI 0.49, 0.67); I 2 = 65%, (Figure 2). ual pain LW 5.6%; and experienced sexual pain-HSW 13.3% L 9.8% LW did. Current data suggest that LW reported fewer difficulties in reaching orgasm.

Risk of Bias
The risk of bias in the included studies was low. The major weakness of the studie was in the control of the confounding variables, which was not performed in six of th eleven studies.

Sexual Satisfaction Results
Sexual satisfaction was evaluated in five studies. Although the evaluation methodo ogies were different, and were therefore not directly comparable, the studies showed n significant differences between LW and HSW in this global assessment.

Frequency of Sexual Intercourse
The frequency of sexual intercourse was presented in four studies involving 533 women, showing a lower frequency for LW when compared to HSW.
A fixed-effects Mantel-Haenszel (M-H) model meta-analysis showed that the pe centage of LW who reported having sexual intercourse at least once a week was signifi cantly lower than that of HSW, OR = 0.57 for LW (95% CI 0.49, 0.67); I 2 = 65%, (Figure 2)

Orgasm Frequency
Six studies involving 38,760 women reported the frequency of subjects who reported having orgasms always or usually.
A meta-analysis using a fixed-effects Mantel-Haenszel (M-H) model showed that there was a statistically significant difference between LW and HSW. LW reported to have orgasms during sexual relations "always or usually" more frequently than HSW, OR = 1.98 (95% CI 1.73, 2.27); I 2 = 87%, (Figure 3).

Orgasm Frequency
Six studies involving 38,760 women reported the frequency of subjects who repo having orgasms always or usually.
A meta-analysis using a fixed-effects Mantel-Haenszel (M-H) model showed there was a statistically significant difference between LW and HSW. LW reported to h orgasms during sexual relations "always or usually" more frequently than HSW, O 1.98 (95% CI 1.73, 2.27); I 2 = 87%, (Figure 3).
Seven studies involving 39,525 women reported the frequency of subjects who ported not having or rarely having orgasms. In the same direction, a meta-analysis u a fixed-effects model found that the percentage of LW who reported "not having or ra having orgasms" during sexual relations was significantly lower than that of HSW, O 0.55, (95% CI 0.45, 0.66); I 2 = 83%, (Figure 3).

Arousal Difficulties
Three studies including 9825 participants reported the frequency of arousal diffi ties. A meta-analysis with a fixed-effects Mantel-Haenszel (M-H) model showed no Seven studies involving 39,525 women reported the frequency of subjects who reported not having or rarely having orgasms. In the same direction, a meta-analysis using a fixedeffects model found that the percentage of LW who reported "not having or rarely having orgasms" during sexual relations was significantly lower than that of HSW, OR = 0.55, (95% CI 0.45, 0.66); I 2 = 83%, (Figure 3).

Arousal Difficulties
Three studies including 9825 participants reported the frequency of arousal difficulties. A meta-analysis with a fixed-effects Mantel-Haenszel (M-H) model showed no statistically significant differences in the percentage of LW with arousal difficulties compared to HSW, OR = 0.79, (95% CI 0.61, 1.01); I 2 = 0%, (Figure 4). In all the meta-analyses, a sensitivity analysis showed that the results remained unchanged after the exclusion of each individual study.

Discussion
Our data included eleven studies and a total of 2294 LW and 42,645 HSW. The results were relatively homogeneous and showed that the percentage of LW who reported to have orgasms during all or most of their sexual relations was almost two times higher than that of HSW. The percentage reporting never or almost never reaching orgasm was higher among HSW. At the same time, LW reported a lower frequency of sexual activity.
In recent decades, the assessment of sexual satisfaction has gained importance and been included in health and well-being indicators. In 2002, the WHO [11], in collaboration with the WAS, highlighted the importance of sexual health, including key factors such as information and sexual pleasure.
Women's sexuality, particularly heterosexual women's sexuality, and predictors of sexual satisfaction are well documented in the literature, with an emphasis on distinctive features such as relational, psychological, and biological dimensions, above and beyond sexual function [32][33][34]. While sexual satisfaction is defined differently by many authors, there are also similarities among most studies. The evaluation of the frequency of orgasm is a relatively simple and transversal measure, although it depends on the self-evaluation and perception of each person.
A discrepancy between sexual satisfaction levels and the frequency of sexual activity was found [35], suggesting that women's sexual satisfaction is multidetermined. Distinctive factors were identified as promoters of sexual satisfaction, such as communication patterns, the quality of a relationship, and sexual compatibility, whereas other factors were described as sexual satisfaction attenuators, such as sexual disorders and discrepancies in sexual desire levels [36].
A review published in 2021 [33] analyzed the predictors of sexual satisfaction in heterosexual women and included a total of 204 studies. Of the variables analyzed by the authors, the following were highlighted as being correlated with women's sexual satisfaction: body image, mental health, physical health, orgasm frequency, relationship satisfaction, sexual communication, sexual desire, sexual frequency, sexual functioning, and sexual practices/variety. The authors of this review noted that the methods used to classify sexual satisfaction were highly heterogeneous across the studies and that there were possibly relevant variables that were only considered in a minority of studies, although they seemed to correlate with female sexual satisfaction, such as: sexual openness or sexual thoughts/fantasies. Data on the predictors of LW's sexual satisfaction have been overlooked, considering that most studies of women's sexual satisfaction and its predictors have been conducted with HSW, leading to a gap in the literature on understanding LW's sexual satisfaction.
A study about midlife women [37] revealed that their sexual satisfaction was partially determined by sexual function and enhanced relational, psychological, and biological dimensions, such as relationship adjustment, psychological well-being, and menopausal symptoms, but was not determined by sexual orientation [38].
In another study [39] that evaluated HSW, LW, and bisexual women, an absence of depressive symptoms, satisfaction in an intimate relationship, better sexual functioning levels, and perceived social support positively predicted sexual satisfaction. Among LW, experiencing internalized homonegativity was also a significant and negative predictor of their sexual satisfaction. A more recent study found evidence that internalized homonegativity does not contribute to lesbian women's sexual satisfaction, whereas identity pride positively contributes to lesbian women's sexual satisfaction [40].
The results of our review are in accordance with several studies that have indicated that LW tend to report higher levels of sexual functioning compared to HSW [41][42][43], and more specifically, that LW report better orgasmic function.
In a study on Dutch college women, LW were also much more likely to experience orgasms during sexual activity with a female partner than HSW [44]. In this study, the likelihood of orgasm was strongly related to receiving glans clitoral stimulation: lesbian women were less likely to receive vaginal stimulation during lovemaking than women in mixed-gender relationships, but those who did were significantly more likely to experience orgasm from it [45].
Possible justifications for the current findings may be related to the different sexual stimulation observed in LW and HSW and the possibility that LW engage in sexual activity and stimulation that facilitate reaching orgasm.
One controversial question about LW's sexual lives is whether they have sexual relations less frequently than HSW [46]. In our review, the frequency of sexual intercourse, evaluated in four studies involving 5339 women, showed a statistically significant difference between lesbian and heterosexual women, with an odds ratio of 0.57 for LW, meaning that the percentage who reported to have sexual intercourse more than once a week was almost half of that for HSW.
One of the problems related to the estimation of sexual satisfaction is that, often, the frequency of sexual intercourse is only considered. Compared to HSW, LW were more likely to usually receive oral sex, to use sex toys, to have sex for longer than 30 min, and engage in gentle kissing, having a broader set of behaviors included their definition of having sex [47][48][49][50].
This review has some limitations that should be taken into consideration. First, there may be publications that were not indexed on the databases searched, and some relevant articles may not have been found. Second, as previously mentioned, the definition of sexual activity and satisfaction could be heterogeneous, as well as the study's methodology.

Conclusions
In conclusion, our review showed that LW achieved orgasm during a sexual interaction more often than HSW. At the same time, LW reported less frequent sexual intercourse when compared to HSW. The percentage of women reporting arousal difficulties did not differ according to their sexual orientation.
It is critical to understand that sexual satisfaction differs according to sexual orientation and to try to understand which factors are associated with a higher satisfaction, especially in minority groups that have been overlooked compared to cisgender, heterosexual people.
These findings have implications for gender and sexual minority health and healthcare optimization.